How to Read & Diagnose Check Engine Light and DTC via BMWLogger

Check engine light, check engine now

We’ve all experienced that annoying CEL light that pops up and immediately we begin to freak out a little bit, but rest assured. We can read & diagnose the check engine light right away by reading the ECU/DME for fault codes via BMWLogger.

Not all error codes will trigger a CEL light and most of CEL lights are caused by emissions related faults, MAF or throttle position sensors. Having no check engine light does not mean your E46 M3 is completely okay. So we recommend checking for codes often to keep up with your maintenance.

All you need is a computer, a cable, your patience and just a few other things and you’ll be able to diagnose and clear codes straight from your garage. Follow the step by step instructions on how to read your fault codes on your BMW E46 M3. Thanks to Bimmer Software for the support. Go visit their site and leave them a donation if it helped you out.

There is absolutely no way to diagnose things quickly and remotely without reading these codes. Descriptions and noises are subjective in nature and not very helpful in diagnosing problems. Let the car tell you exactly what is wrong, it is the reason why BMW designed those sensors.

Tools Required

A FTDI based OBD2 diagnostic cable such as a BMTechnic cable/BM or a KKL Vag-Com cable or our recommended generic D+KCAN FTDI

A trickle charger that can supply 10A to your car whilst flashing. I use a CTEK MXS 10 (Recommended, but not always required if your battery is good)

An E46 M3

Reading ECU/DME Error Codes

1. Download and extract BMWLogger.
2. Plug in your D-CAN FTDI cable to your Windows laptop and car.
3. Turn your car key to position 2.
4. Open BMWLogger. Keep in mind that BMWFlash must be closed in order to use BMWLogger.
5. Press the tool/gear icon on the as circled below.

6. Select D-CAN or FT232R from the drop-down menu, and press save. If you bought our recommended cable, you will see FT232R on the drop-down menu instead of D-CAN. You do not need to change anything else. I

7. After doing so, you will see the bottom left box turn green which says “D-CAN Detected. Ready To Log.”